The relationship between cognitive decline and motor dysfunction in Parkinson’s disease: A focused mini‐review on cognitive‐locomotor dual‐task interference

Abstract

Parkinson's disease (PD) is a chronic and progressive degenerative disorder of the central nervous system with a prevalence of roughly 1% in the population over the age of 60. 1 Patients with PD display characteristic motor symptoms such as rigidity, bradykinesia, resting tremor, and postural instability. PD is also characterized by non-motor symptoms including REM behavior disorder, hyposmia, constipation, depression, and cognitive impairment. 2 Cognitive impairments are often observed in the early stages of the disease and involve multiple cognitive domains including executive function, attention/ working memory, and visuospatial function. 3 Accumulating evidence reveals the vital role of cognitive processing in planning motor behavior and their close interrelationship in healthy subjects. 4,5 It has also been suggested that a decline in cognitive status and motor symptoms are interrelated in the clinical course of PD. 6 Representative examples of cognitive and motor relationships are observed during the dual-task paradigm, which demonstrates that the performance of each task is affected by the concurrently performed other task. Previous studies have revealed that patients with PD commonly have difficulties in performing two or more tasks simultaneously and show larger dual-task interference than healthy subjects, 7-10 which highlights the importance of the cognitive-motor relationship in the pathophysiology of PD.